diff --git a/xpcom/reflect/xptinfo/xptinfo.h b/xpcom/reflect/xptinfo/xptinfo.h
index 148867d619d4..4f3661564385 100644
--- a/xpcom/reflect/xptinfo/xptinfo.h
+++ b/xpcom/reflect/xptinfo/xptinfo.h
@@ -198,8 +198,6 @@ public:
             NS_PRECONDITION(idx < GetParamCount(),"bad arg");
             return params[idx];
         }
-    const nsXPTParamInfo GetResult() const
-        {return result;}
 private:
     nsXPTMethodInfo();  // no implementation
 // NO DATA - this a flyweight wrapper
diff --git a/xpcom/typelib/xpt/xpt_struct.cpp b/xpcom/typelib/xpt/xpt_struct.cpp
index 4c847ae80c7c..00c33b063a3b 100644
--- a/xpcom/typelib/xpt/xpt_struct.cpp
+++ b/xpcom/typelib/xpt/xpt_struct.cpp
@@ -316,7 +316,12 @@ DoMethodDescriptor(XPTArena *arena, NotNull<XPTCursor*> cursor,
             return false;
     }
 
-    if (!DoParamDescriptor(arena, cursor, &md->result, id))
+    // |result| appears in the on-disk format but it isn't used,
+    // because a method is either notxpcom, in which case it can't be
+    // called from script so the XPT information is irrelevant, or the
+    // result type is nsresult.
+    XPTParamDescriptor result;
+    if (!DoParamDescriptor(arena, cursor, &result, id))
         return false;
 
     return true;
diff --git a/xpcom/typelib/xpt/xpt_struct.h b/xpcom/typelib/xpt/xpt_struct.h
index bccace6b164e..d9d73cf52909 100644
--- a/xpcom/typelib/xpt/xpt_struct.h
+++ b/xpcom/typelib/xpt/xpt_struct.h
@@ -286,7 +286,7 @@ struct XPTParamDescriptor {
 struct XPTMethodDescriptor {
     char                *name;
     XPTParamDescriptor  *params;
-    XPTParamDescriptor  result;
+    //XPTParamDescriptor  result; // Present on disk, omitted here.
     uint8_t             flags;
     uint8_t             num_args;
 };